Construction of Virtual Data Views

A virtual data view is essentially a physical data
view on which certain transformation actions have been defined. The transformation
actions take place in real time, to create the virtual data view. The following
figure shows how transformation actions are defined on a physical data view
to create a virtual data view.

Figure 18–1 Virtual Data View

In addition to the transformation actions, certain properties can be
defined on a data view, which restrict the way in which data can be managed
through that data view. The additional virtual data view properties are described
in Additional Virtual Data View Properties.

Caution –

Virtual data views imply a performance impact. The significance
of the performance impact depends on several factors including the size of
the physical data source, the complexity of the transformation, and the complexity
of any virtual ACIs you might use.